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/*
 * Copyright 2016-2022 The OSHI Project Contributors
 * SPDX-License-Identifier: MIT
 */
package oshi.hardware.platform.mac;

import java.util.ArrayList;
import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.sun.jna.Pointer;
import com.sun.jna.platform.mac.CoreFoundation.CFDataRef;
import com.sun.jna.platform.mac.CoreFoundation.CFStringRef;
import com.sun.jna.platform.mac.CoreFoundation.CFTypeRef;
import com.sun.jna.platform.mac.IOKit.IOIterator;
import com.sun.jna.platform.mac.IOKit.IORegistryEntry;
import com.sun.jna.platform.mac.IOKitUtil;

import oshi.annotation.concurrent.Immutable;
import oshi.hardware.Display;
import oshi.hardware.common.AbstractDisplay;

/**
 * A Display
 */
@Immutable
final class MacDisplay extends AbstractDisplay {

    private static final Logger LOG = LoggerFactory.getLogger(MacDisplay.class);

    /**
     * Constructor for MacDisplay.
     *
     * @param edid a byte array representing a display EDID
     */
    MacDisplay(byte[] edid) {
        super(edid);
        LOG.debug("Initialized MacDisplay");
    }

    /**
     * Gets Display Information
     *
     * @return An array of Display objects representing monitors, etc.
     */
    public static List getDisplays() {
        List displays = new ArrayList<>();
        // Iterate IO Registry IODisplayConnect
        IOIterator serviceIterator = IOKitUtil.getMatchingServices("IODisplayConnect");
        if (serviceIterator != null) {
            CFStringRef cfEdid = CFStringRef.createCFString("IODisplayEDID");
            IORegistryEntry sdService = serviceIterator.next();
            while (sdService != null) {
                // Display properties are in a child entry
                IORegistryEntry properties = sdService.getChildEntry("IOService");
                if (properties != null) {
                    // look up the edid by key
                    CFTypeRef edidRaw = properties.createCFProperty(cfEdid);
                    if (edidRaw != null) {
                        CFDataRef edid = new CFDataRef(edidRaw.getPointer());
                        // Edid is a byte array of 128 bytes
                        int length = edid.getLength();
                        Pointer p = edid.getBytePtr();
                        displays.add(new MacDisplay(p.getByteArray(0, length)));
                        edid.release();
                    }
                    properties.release();
                }
                // iterate
                sdService.release();
                sdService = serviceIterator.next();
            }
            serviceIterator.release();
            cfEdid.release();
        }
        return displays;
    }
}